EP0080379A1

EP0080379A1 - Connector assembly for liquid flow systems

Info

Publication number: EP0080379A1
Application number: EP82306262A
Authority: EP
Inventors: Poul Tranberg
Original assignee: SCANDINAVIAN MEDICAL SUPPLY Ltd
Current assignee: SCANDINAVIAN MEDICAL SUPPLY Ltd
Priority date: 1981-11-25
Filing date: 1982-11-24
Publication date: 1983-06-01
Also published as: DK524982A; AU9088182A; FI77775B; NO152864B; JPS58109060A; ATE18720T1; NO823933L; NZ202591A; ES517639A0; NO152864C; DK159053B; FI824026A0; DK159053C; CA1199354A; ZA828660B; EP0080379B1; FI77775C; DE3270165D1; ES8400668A1; AU554339B2

Abstract

A self-sealing, sterile connector assembly for use in a surgical drainage system includes releasably cooperable plug and socket parts (3, 4), the plug part (3) incorporating a slidable sleeve valve (3d), and the socket (4) incorporating a normally closed disc valve (5). Both valves are actuated, i. e. opened and closed respectively, by the relative plugging and unplugging movement between the plung and socket parts. The plug and socket parts (3, 4), and the valves (3d, 5), are so configured that, during unplugging movement between the parts (3, 4), the valves (3d, 5) close in a manner which avoids the formation of any voids therebetween capable of accommodating sufficient liquid to form drips.

Description

This invention relates to a plug-and-socket type connector assembly incorporating a cut-off valve which is intended to be substantially drip-proof in operation, the connector assembly being primarily intended to be incorporated between a surgical drain of a patient and a liquid receptacle such as a plastics bag.
Various self-sealing connections between a drainage hose and a liquid receptacle are known, but with prior constructions liquid spillage tends to occur during the process of disconnecting the drainage hose from the receptacle, which process, in some cases, must take place several times per day. Since, in surgical drainage, the said liquid is often urine, blood or other liquid, containing pus, it will be evident that such spillage will be considered as hazardous, whether it occurs when a patient is in hospital or in private care.
Whilst International Application No: W080/0157 and United States Patent No. 3,642,037 disclose connections which claim to avoid such spillage, these connectors are relatively complicated, and expensive to manufacture.
It is an object of the present invention to provide a self-sealing plug-and-socket type connector assembly incorporating a cut-off valve arrangement which is not only capable of effectively eliminating spillage or dripping during connection and disconnection, but is also capable of being manufactured relatively simply and inexpensively.
From one aspect, the present invention provides a connector assembly for use in a liquid flow system, such as a surgical drainage system, including releasably coo_Derable plug and socket Darts, one of the parts incorporating a first valve and the other of the parts incorporating a second valve, operable to permit liquid to flow between the parts when plugged together, and effectively to prevent liquid spillage from the parts when unplugged, both valves being actuated by the relative plugging and unplugging movement between the plug and socket parts, the valves being arranged and adapted, during unplugging movement between the parts, to close in a manner which avoids the formation of any voids therebetween capable of accommodating sufficient liquid to form drips.
From another aspect, the present invention provides a connector assembly for use in a liquid flow system, including releasably cooperable plug and socket parts incorporating a valve arrangement for cutting-off liquid flow through the plug and socket parts when unplugged, the plug part having a slide valve and comprising a tubular plug body closed at one end and having at least one opening near the closed end, and a sleeve surrounding the plug body, the plug body and sleeve being relatively slidable between a valve-closed position in which the sleeve closes the opening in the plug body, and a valve-open position in which the sleeve does not close the opening, the socket part comprising a tubular socket body having an open end for receiving the closed end of the plug body, and a flap valve spaced from the open end of the socket body, plugging movement between the plug and socket parts being operable both to cause displacement of the flap valve, and of the plug body and sleeve, to their valve-open positions in which a liquid path is established between the plug and socket parts via the flap valve and opening, and unplugging movement between the plug and socket parts being operable both to cause displacement of the flap valve, and of the plug body and sleeve, to their valve-closed positions whilst effectively preventing or substantially reducing dripping.
The invention also consists in a liquid flow system incorporating one or more connector assemblies as above defined.
The liquid flow system may comprise a surgical drainage system including a liquid receptacle, a catheter or other drain means cooperable with a patient, and a liquid line, interconnecting the drain means and receptacle, incorporating a connector assembly as above defined.
In one embodiment, the components of the valve are integrated parts of the connecting members, i.e. the plug and socket parts, between the drainage line or hose and the receptacle or bag. The connecting action itself causes a valve to open in both the plug part and the socket part and thereby allows the passage of liquid through the system. Likewise, both valves are caused to close immediately the system is disconnected, avoiding waste from the connection or joint.
The plug part and socket part are, respectively, welded or glued to the ends of lengths of drainage hose leading to the bag and a catheter or other drain means. The tubular plug body, which is closed by an externally planar transverse end wall at its far or distal end, is provided with side openings in its cylindrical surface or wall quite near to the end wall. The tubular sleeve is slidable lengthwise between two extreme positions, namely between valve-open and valve-closed positions. This assembly can slide into the tubular socket body of the socket part to a fully introduced position of the sleeve, the sleeve and plug body moving in unison to this position. The plug body is then advanced a small distance further, causing the sleeve to slide back relative to the plug body, to a position in which it clears the openings in the plug body and the openings communicate with the interior of the socket part. At the same time, the distal end of the plug body will lift the flap-valve at the bottom or proximal end of the socket body and thus allow a liquid to flow through the system.
When, due to the need to exchange the bag, the plug part has to be disengaged from the socket part, the plug body, as it is being withdrawn, will initially lower the flap-valve, allowing it to close, and at the same time cause the sleeve to slide forwards and cover the openings of the plug body. These movements will follow, surface to surface,and in no situation leave empty spaces or voids for liquid. It is of great importance, apart from the function of the valve arrangement described, to achieve an economic solution, as it must be remembered, that the article is to be considered as disposable.
In order that the invention may be more readily understood, reference will now be made to the accompanying drawings, in which:-

Figure 1 is a schematic fragmentary side view of part of a surgical drainage system incorporating a connector assembly embodying the invention, with the plug and socket parts of the assembly partially sectioned, and shown in their disconnected, valve-closed condition; and
Figure 2 is a view, similar to Figure 1, with the plug and socket parts shown in their interconnected, valve-open condition, on an enlarged scale.

The surgical drainage system includes a synthetic plastics bag 1 connected to a drainage line or hose 2a, 2b incorporating a coupling or connector assembly comprising a male or plug part 3 and a female or socket part 4.
The plug and socket parts are formed, for example moulded, from suitable resilient, self-supporting, synthetic plastics material or materials.
The plug part 3 includes a tubular, cylindrical body 3a, one end of which is secured at 2e, for example by welding or gluing, within an end of the section 2a of the drainage hose directly connected to the bag 1. The outer or distal end of the plug body 3a is closed by a transverse end wall 3b and,adjacent the end wall, the cylindrical side wall of the plug body is perforated by circumferentially extending openings 3c. A valve element comprising a cylindrical sleeve 3d closely fits the outer cylindrical surface of the plug body. The plug body is slidable axially within the sleeve 3d from a retracted or valve-closed position as shown in Figure 1, in which the outer or distal end of the sleeve is substantially flush with the planar outer surface of the transverse end wall 3b, and the sleeve overlies and seals off the openings 3c, to a valve-open position as shown in Figure 2, in which the distal end of the plug body 3a is advanced relative to the sleeve 3d to expose and open the openings 3c. The proximal end of the sleeve is provided with internal and external annular flanges 3e and 3f respectively. The internal flange 3e engages in a reduced diameter portion of the plug body, and is cooperable with stops formed by opposed shoulders 3g and 3h of the body to predetermine the range of sliding movement of the sleeve relative to the plug body. The shoulder 3h is formed at one end of an annular collar 3i integral with the plug body and formed with integral diametrically opposed pins 3k forming part of a bayonet-type locking arrangement.
The sleeve 3d is initially assembled to the plug body 3a by pressing the flanged proximal end of the sleeve over the distal end of the plug body, and to simplify this operation, the internal flange 3e is formed with a tapered radially inner surface to provide a lead-in. 2a
The hose section/may terminate within the bag 1 in a non-return valve 2c (Fig. 2) which prevents liquid or gas within the bag from passing back up the hose.
The socket part 4 is also tubular, and has a reduced diameter end portion 4a secured, for example by welding or gluing, to an end of the section 2b of drainage hose intended to be connected to a catheter or other drain. The end portion 4a communicates with one end of an enlarged diameter cylindrical/portion 4b defining a tubular chamber, the other end of the chamber communicating with a tubular socket body 4c internally dimensioned to slidably receive the plug part 3. The cylindrical portion 4b is sufficiently resilient or flexible to permit it to be compressed manually, and the hose section 2b terminates, within the chamber, in a - non-return valve 2d which prevents liquid or gas, and any bacteria etc., within the chamber from passing back up the hose section. The non-return valve 2d (and the valve 2c) may be of the type which comprises a length of open-ended, flat or collapsed flexible tubing, formed, for example, from two elongate flat strips of plastics material welded together along their longer edges.
The socket body 4c is provided, at its proximal end, with an internal annular flange 4d which serves as a stop for the sleeve 3d. The opening in the flange 4d is bounded by an annular ridge forming a seat 4e for a flap or disc valve element 5. The valve element 5 includes a circular, flat elastomeric sealing disc 5a bonded or otherwise secured to the flat end face of a closed-ended cylindrical support member 5b located within the cylindrical portion or chamber 4b. The disc valve element 5 is displaceable, and is biased by a coil spring 5c so as normally to urge the disc 5a towards the seat 4e to close, or tend or close, the opening in the flange 4d.
The disc valve element 5 and bias spring 5c are located in a perforate housing 4f secured to the base of the cylindrical portion or chamber 4b,with the spring 5c maintained in compression between the disc valve element 5 and the underside of the top or end wall of the housing 4f. The inner diameter of the flange 4d, i.e. the diameter of the opening in the flange, is approximately the same as the external diameter of the distal end region of the plug body 3a, so that the latter end region will be snugly slidably received by the flange when the plug and socket parts are connected together as shown in Figure 2. The cylindrical passage within the socket body 4c is provided with a reduced diameter region 4g adjacent the flange 4d, which is slightly smaller in diameter than the distal end of the sleeve 3d. Between the region 4 and an annular recess 4h, the internal diameter of the socket body 4c approximates or is slightly greater than the diameter of the sleeve 3d but less than the diameter of the external flange 3f. The distal region of the passage in the socket body 4c, for example the region between the recess 4h and the open end of the body, may be internally stepped or tapered to provide an increased-diameter lead-in portion to facilitate insertion of the sleeve 3d. This distal region is also formed with a pair of slots 4i, forming part of the bayonet-type locking arrangement, and cooperable with the pins 3k.
The connector assembly operates as follows:-

In the disconnected condition of the plug and socket parts 3 and 4 shown in Figure 1, their associated valves are both closed. More specifically, the disc valve element 5 sealingly engages the valve seat 4e on the flange 4d, preventing liquid which flows from a patient, via a catheter connected to the hose section 2b, into the chamber in the cylindrical portion 4b, from flowing out of the socket body 4c. The distal end of the plug body 3a is retracted relative to the sleeve 3d, closing the openings 3c so as, after use and disconnection.of the bag 1, to prevent flow of liquid from the hose section 2a connected to the bag. However, it is not essential for the sleeve 3d to close the openings 3c of a plug part of an unused bag prior to connection.

When the plug part 3,disposed as shown in Figure 1, is introduced into the socket body 4c, the frictional cooperation between the plug body 3a and sleeve 3d is preferably initially greater than that between the sleeve 3d and internal surface of the socket body 4c. Therefore, the plug body and sleeve travel together, i.e. in their valve-closed position (Figure 1),until the external flange 3f engages the distal end of the socket body 4c. Further insertion of the plug part then causes the plug body to advance relative to the sleeve until the proximal end of the sleeve engages the shoulder 3h. Still further insertion of the plug part causes the flange 3f to be flexed or compressed, and the plug body and sleeve advance in unison to the position shown in Figure 2, in which the flange 3f snaps into the recess 4h, and the closed distal end of the plug body passes through the flange 4d and lifts the disc valve element 5 from its seat 4e against the action of the spring 5c. Thus, liquid is free to flow through the socket part, through the perforate housing 4f, through the openings 3c, and into the plug part. This position is determined by the engagement and locking of the pins 3k in the slots 4i of the bayonet-type locking arrangement. Since, in this position, the sleeve 3d sealingly cooperates with the plug body 3a and socket body 4c, the distal end of the sleeve engages the flange 4d and sealingly cooperates with the reduced diameter region 4g, and the plug body is snugly received in the opening in the flange 4d, leakage between the plug and socket parts is prevented.
If due to the friction between the sleeve and plug body 3a, the sleeve does not slide back on the plug body when, during insertion, the flange 3f engages the socket body, it will do so when its distal end encounters the region 4g. In any event, the sleeve will be positively driven fully home against the flange 4d, and the flange 3f will be snapped into the recess 4h, by engagement of the sleeve with the shoulder 3h.
Should the liquid flowing through the system tend to block the openings in the housing 4f and/or the openings 3c, for example due to coagulation, the flexible cylindrical socket portion 4b may be compressed, closing the non-return valve 2d, to pump or force the liquid through the openings and clear the blockage. The valve 2d isolates the patient from contaminants and pressure buildups downstream of the valve, and the valve 2c likewise prevents any contaminants, liquid, and pressure buildups in the bag from being transmitted to the connector assembly.
During withdrawal of the plug part from the socket part, the following procedure occurs. After the plug and socket parts have been relatively rotated to release the bayonet-type locking arrangement, the plug body 3a is firstly retracted relative to the socket body 4c and sleeve 3d until the upper surface of its transverse end wall 3b is flush with the upper edge of the valve seat 4e, so that the elastomeric disc 5a of the disc valve element 5 will seat and seal on the valve seat 4e without any significant voids, and therefore without any significant amounts of liquid being trapped, between the planar opposed surfaces of the disc 5a and distal end of the plug body. Withdrawal of the plug part alone continues since the sleeve is locked in its uppermost position by the engagement of its flange 3f in the recess 4h, until the plug part passes down through the opening in the flange 4d and the upper surface of its transverse end wall 3b is substantially flush with the upper or distal end of the sleeve 3d, so that the openings 3c are closed by the sleeve. In this condition, the flange 3e at the lower end of the sleeve 3d engages the shoulder 3g on the plug body, and as a result, further withdrawal of the plug body disengages the flange 3f from the recess 4h, and the sleeve and plug body (in their Figure 1 position) will be withdrawn in unison from the socket body until separated therefrom.
From the foregoing, it will be apparent that, whilst separational movement between the plug and socket parts is occurring, before the distal end of the plug body 3a is withdrawn from the opening in the flange 4d in the socket body 4c, the disc valve element 5 will follow the distal end of the plug body 3a down and rest on the valve seat 4e on the flange 4d, closing the opening therein, without at any time leaving any space between the disengaging members. Thus, separation is achieved without any dripping or other spillage or leakage.
According to a feature of the illustrated invention, the non-return valve 2b may, prior to assembly, be secured to a short length of pipe or hose, the latter being secured within the end portion 4a of the socket part. In this way, the valve 2b may be positively centrally located within the cylindrical portion or chamber 4b to ensure that the valve does not contact the cylindrical wall of the chamber which may otherwise cause the valve to malfunction, for example, remain partially open, even when the pressure in the chamber exceeds the pressure in the hose section 2b.
In order to prevent the transparent cylindrical portion 4b from becoming detached from the socket body 4c when the former is manually compressed, the socket body 4c may include a pair of concentric walls between which the lower end of the cylindrical portion 4b is mechanically located, and bonded or otherwise anchored in place. The cylindrical portion 4b may also be thicke.ned adjacent its lower end to overlie the outer of the pair of concentric walls. The inner concentric wall may be provided by a flange on a separate re-entrant component, bonded into the socket body 4c, which also forms the housing 4f.
It is desirable to make the drainage hose for surgical drains from polythene since the hose will then be relatively flexible and soft, and therefore more comfortable to the patient. However, in prior drains, it is then necessary also to make the bag of polythene in order to enable the hose and bag to be readily bonded together. However, disposal of the polythene bags gives rise to problems since polythene, when incinerated, gives off corrosive or toxic by-products. In the illustrated embodiment, however, the hose section 2b constitutes the major proportion of the overall length of the drainage hose can be formed from polythene, whereas the relatively short hose section 2a, and therefore the bag 1,can be formed from polyvinyl chloride. Polyvinyl chloride can not only be disposed of by incineration without the production of toxic or corrosive by-products, but it is also a relatively cheap material to employ, and its use enables the hose section and bag assembly to be manufactured at a much higher rate.
From the foregoing, it will be seen that there is provided a particularly advantageous form of effectively drip proof and contamination proof connector assembly. The connector assembly is relatively simple and foolproof to manipulate, and is relatively simple and inexpensive to manufacture and assemble since it incorporates a minimum of individual components, all or the majority of which may be readily formed, for example moulded, from synthetic plastics materials. It is economically viable for the connector assemblies to be treated as disposable items, avoiding the problensand expense of sterilization associated with re-use. The socket part and associated catheter may be retained connected to a patient, and used with a succession of plug parts and associated bags which are removed and disposed of when the bags are filled. When filled bags are unplugged,due to the effectively drip and void free valving arrangement, the risk of contamination being transmitted from or to the unplugged parts is effectively eliminated or significantly reduced.
It will be understood that various modifications may be made without departing from the scope of the present invention.
For example, the recess 4h in the socket body 4c could be replaced or supplemented by one or more ribs with which the sleeve flarge 3f is releasably cooperable. Other means may be provided to ensure that, during and after removal of the plug part from the socket part, the sleeve is urged into, and/or indexed in, its closed position. Although, in the specific embodiment, the connector assembly is arranged with its plug part downstream of the socket part, the positions could be reversed. The disposition shown in the illustrated embodiment, however, has-the advantage that the valve element 5 is assisted in closing by the normal flow of liquid through the drainage system, and the element is conveniently disposed in the chamber in the enlarged diameter socket portion 4b. The flap valve element 5 could, furthermore, take a form other than that of a disc valve, for example it could comprise a flexible flap valve secured or hinged at one side to the flange 4d.
Although, in the illustrated embodiment, connection and disconnection of the plug and socket parts is effected simply by a manual push or pull action respectively, accompanied by a twisting action to lock or unlock the bayonet-type locking arrangement, the locking arrangement could be omitted, or could take the form of a snap-acting connection, screw thread-type connection, or other type of releasable lock.
The shape, configurations and materials of the various components may be changed, and the connector assembly may be applied to liquid flow systems other than surgical drainage systems.
Although the plug and socket parts in the illustrated embodiment are permanently secured to the hose sections, they could alternatively be press-fitted or otherwise releasably attached to the hose sections or other fluid lines, etc. The plug and socket bodies could be formed, for example molded, integrally with the ends of their respective fluid lines, etc.
The diameter of the disc valve element 5 may be reduced to a value approaching that of the valve seat 4e, and may be prevented from lateral displacement relative to the valve seat to positions in which it may not fully cover the valve seat by means of upright rib-like guides within the housing 4f or on the element 5b. The spring 5c, at its. upper end,may be located laterally, for example located in a recess in the top of the housing 4f.
The perforate housing 4f could be replaced by a rib or equivalent mounted in the chamber in the socket part, with which the spring 5c, a sponge-like pad, or equivalent resilient element, cooperates. Alternatively, the housing or rib, and resilient element, may be omitted, the disc or flap valve element relying on its own mass or resilience respectively, and/or the liquid pressure, to bias it to its closed position.
The range of sliding movement of the sleeve may be determined by means other than the sleeve flange 3e which cooperates, alternatively, with the shoulders 3g and 3h. For example, the shoulder 3h may be omitted, and instead, the flange 3e or equivalent may cooperate, with the distal end of the hose section 2a connected to the bag 1.
The flange 4d may be omitted, and the sleeve may be permitted to project through the opening in the valve seat in the socket body 4c. In this event, the fully inserted position of the plug body will be determined by the bayonet-type locking arrangement or other stop means. The distal end of the plug body may have an annular shoulder of the same diameter as that of the seat opening and sleeve, against the underside of which the sleeve abuts in its valve-closed position. The transverse upper surfaces of the end wall 3b and the latter annular shoulder will be effectively flat and coplanar to ensure that, during unplugging, no voids are formed between the latter surfaces and the underside of the valve element as it closes on its seat, to avoid formation of drips.
The drainage system may be employed with a hospitalised patient, although it could be used to advantage with a mobile patient as a urinary drain. In the latter case, since the likelihood of clots forming in the drained fluid is remote, it is not necessary to provide the pumping chamber 4b, and this may be omitted for reasons of space-and weight-saving, cost and convenience. The non-return valve 2d may be omitted, and the socket end portion 4a may be bonded directly to, or integrated with, the outer upper side wall of the socket body 4c.
In addition to, or as an alternative to, the bayonet-type locking arrangement, resilient cooperable snap-acting means may be provided to signify to a user when the plug and socket parts are fully engaged, and/or to index the sleeve in its valve-closed position during plugging or unplugging. For example the sleeve and/or plug body and/or socket body may be provided with annular ribs or other projections, and complementary cooperable grooves or depressions.
The system, for example the cylindrical socket portion 4b, may be provided with a vent or filter arrangement capable of venting gas (but not liquid)from the chamber in the event of a pressure build-up. Additionally or alternatively, such a vent or filter arrangement may be incorporated in the hose section 2b or in the connection for connecting the hose section to the catheter. The vent arrangement may also include a portion penetrable by a syringe needle or luer to permit injection into or extraction from the arrangement. One or both of the non-return valves 2c, 2d, may be omitted, or replaced by other types of valves.

Claims

1. A connector assembly for use in a liquid flow system, such as a surgical drainage system, including releasably cooperable plug and socket parts (3, 4), one of the parts (3) incorporating a first valve (3d) and the other of the parts (4) incorporating a second valve (5), operable to permit liquid to flow between the parts when plugged together, and effectively to prevent liquid spillage from the parts when unplugged, both valves being actuated by the relative plugging and unplugging movement between the plug and socket parts, characterised in that the valves (3d, 5) are arranged and adapted, during unplugging movement between the parts (3, 4), to close in a manner which avoids the formation of any voids therebetween capable of accommodating sufficient liquid to form drips.

2. A connector assembly as claimed in claim 1, characterised in that the plug part (3) has a slide valve and comprises a tubular plug body (3a) closed at one end (3b) and having at least one opening (3c) near the closed end, and a sleeve (3d) surrounding the plug body, the plug body (3a) and sleeve (3d) being relatively slidable between a valve-closed position (Fig. 1) in which the sleeve closes the opening in the plug body, and a valve-open position (Fig. 2) in which the sleeve does not close the opening, the socket part (4) comprising tubular socket body (4c) having an open end for receiving vhe closed end of the plug body (3a), and a flap valve (5) spaced from the open end of the socket body, plugging movement between the plug and socket parts (3,4) being operable both to cause displacement of the flap valve (5 ), and of the plug body (3a) and sleeve (3d), to their valve-open positions in which a liquid path is established between the plug and socket parts via the flap valve ( 5 ) and opening (3c), and unplugging movement between the plug and socket parts being operable both to cause displacement of the flap valve ( 5 ), and of the plug body (3a) and sleeve (3d), to their valve-closed positions whilst effectively preventing or substantially reducing dripping.

3. A connector assembly as claimed in claim 2, wherein the closed end of the plug body (3a) is closed by an externally generally planar transverse end wall (3b), and wherein the flap valve (5 ), in the valve-closed position, has a generally planar transverse face presented towards the open end of the plug body-receiving open end of the socket body (4c), and sealingly cooperates with a valve seat (4e) having an opening dimensioned to closely receive the end wall (3b), whereby, when in the valve-closed position at the transition between the valve-open and valve-closed positions, the end wall (3b) cooperates closely with the flap valve ( 5 ) and the opening in the valve seat (4e) to prevent the occurrence of. any significant liquid-accommodatable voids therebetween.

4. A connector assembly as claimed in claim 3, wherein, during movement from the valve-open towards the valve-closed position, the frictional cooperation between the sleeve (3d) and the socket body (4c) is greater than the frictional cooperation between the sleeve (3d) and the plug body (3a), whereby, during unplugging movement, the plug body initially slides relative to the sleeve to a position in which the sleeve closes the opening (3c) in the plug body before the sleeve and plug body move in unison further towards the fully unplugged position.

5. A connector assembly as claimed in claim 4, including means (3f,4h) on the exterior of the sleeve (3d) and within the socket body (4c) adapted to cooperate in the valve-open position to releasably lock the sleeve against axial movement relative to the socket part during initial unplugging movement of the plug body.

6. A connector assembly as claimed in claim 5, wherein said cooperating means comprise a resilient flange (3f) on the sleeve cooperable with a recess (4h), or at least one rib, within the socket body.

7. A connector assembly as claimed in claim 4, 5 or 6, wherein, during at least initial plugging movement, the frictional cooperation between the sleeve (3d) and the socket body (4c) is less than the frictional cooperation between the sleeve and the plug body (3a) whereby the sleeve remains in a position on the plug body in which it closes the opening (3c) in the plug body during initial plugging movement.

8. A connector assembly as claimed in claim 4, 5, 6 or 7, wherein the generally planar transverse end wall (3b) of the plug body is generally co-planar with the end of the sleeve (3d) in the valve-closed position.

9. A connector assembly as claimed in any of claims 3 to 8, wherein the sleeve (3d) is cooperable with the valve seat (4e) during plugging movement to ensure that the plug body is advanced through the opening in the valve seat (4e) relative to the sleeve (3d) to a position in which the sleeve does not close the opening (3c) in the plug body, in which the end wall (3b) cooperates with the flap valve (5) to disengage it from the valve seat (4e), and in which the opening (3c) is located on the side of the valve seat (4e) remote from the sleeve.

10. A liquid flow system, or liquid flow apparatus, incorporating one or more connector assemblies as claimed in any preceding claim, and comprising a surgical drainage system or apparatus including a liquid receptacle (1), a catheter or other drain means cooperable with a patient, and a liquid line (2), interconnecting the drain means and receptacle, incorporating the connector assembly.

11. The connector assembly, system or apparatus as claimed in any preceding claim, including at least one non-return valve (2c or 2d) to prevent flow in one direction through the connector assembly when in the valve-open position, and wherein the second part (4) includes a flexible housing (4b) containing the second valve (5), the housing (4b) being manually compressible to force liquid through the connector assembly when in the valve-open position.